The population in the US and worldwide is aging rapidly~ the United Nations estimates that by 2050, for the first time in history, the population f older people will exceed the population of younger people. At the same time, obesity is rapidly reaching epidemic proportions. The World Health Organization states that worldwide, obesity has doubled since 1980, and in 2008, 1.5 billion adults were obese. The combination of an aging, overweight population has serious implications for cognitive health, as aging and obesity are both associated with cognitive decline, as are risk factors that are increased by both aging and obesity, such as insulin resistance and hypertension. Poor cognitive function is a significant public health concern, particularly in older adults, because it can reduce an individual's ability o perform activities of daily living or follow prescribed health care activities, leads to increased institutionalization and loss of independence. There is good evidence that aerobic exercise benefits cognitive function in older adults. Exercise also improves glucose regulation and insulin sensitivity, and may lower inflammation, all potential mechanisms for exercise-induced improvement in cognition. Intentional weight loss through reduced caloric intake improves metabolic risk factors for cognitive decline more than exercise alone, suggesting that weight and fat loss may enhance the cognitive benefits of exercise. However, whether weight loss is safe and healthy for older adults is a matter of controversy, and some studies actually show that higher body weight is associated with better cognition in older adults. Thus, it is unknown whether adding caloric restriction to an aerobic exercise intervention provides an additive benefit on cognition, and brain structure and function, beyond exercise alone in obese older adults. The proposed study addresses concerns of national and worldwide health significance by investigating the effects of adding weight loss to exercise in obese older adults as a potential avenue for remediation of obesity-related cognitive decline in older adults. This study also provides an excellent avenue for training for the candidate, whose overall career goal is to become an independent clinical and translational researcher. Her strong background in cognitive neuroimaging of aging will be augmented by training in clinical trial research and behavioral weight loss interventions~ new analysis techniques~ and knowledge of obesity, dementia, and other geriatric syndromes. This training will allow her to design new trials that further investigate the relationships between modifiable risk factors for metabolic disease and the brain and cognition.